Mechanical and reactive properties of PTFE/Al/MoO₃ composites

Abstract

PTFE/Al/MoO3 composites with different PTFE concentrations were prepared by mold pressing and sintering. The materials were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), in addition, the properties of the composites under quasi-static compression and dynamic impact were also studied. The results indicate that, the strength of PTFE/Al/MoO3 composites is increased first and then decreased with the increase of PTFE, reaches the maximum of 80MPa when the volume fraction of PTFE is 70%. Meanwhile, these specimens can ignite under quasi-static compression conditions, with a huge explosion and bright flames, while no ignition phenomenon was observed in the other specimens under the same conditions. Under the dynamic impact conditions, all of the PTFE/Al/MoO3 composites can ignite, but with the increase of PTFE, the degree of intensity is decreased gradually. The reaction products are AlF3, Al2O3, Mo and C, indicating that the redox reactions of Al and PTFE, Al and MoO3have both been triggered. Under the dual influence of material strength and composition, the energy required for ignition of PTFE/Al/MoO3 composites tends to drop first and then increase with the increase of PTFE.

Keywords

• PTFE/Al/MoO₃
• thermite
• quasi-static compression
• dynamic impact